pressure guage to diag EGR/headgasket leaks

the_twig_187 · January 16, 2015

so I have watched some videos on youtube of two different tech which I deem to be very confident and professional techs. both of these techs use a 0-30psi pressure gauge and some 3/8 heater hose to tee into the degas bottle and then they run the gauge into the cab to observe the pressure building while under load to determine if the problem is coming from the egr cooler or the headgaskets. both techs claim that a normal operating range for coolant pressure in their areas is approx. 10-12 psi and that if you are seeing 15-16-+ psi that you have combustion pressure in the cooling system. they both say that if the pressure builds to 15+ psi in a matter of seconds that it is evident of an EGR cooler leak and that if it slowly builds to 15+ psi that it is more evident of a headgasket issue.

does anyone have any experience with this tool as a means of diaging egr/headgasket problems?

does it work?

is it accurate?

thanks

Chris

tonybullitt · January 16, 2015

From tsb 9-8-3

Road Test For Leaking Head Gaskets - Setup And Observations:
Install the vehicle measurement module (VMM) pressure vacuum transducer (PVT), or Rotunda Pressure Adapter Kit 014-00761, or equivalent. (Figure 4)

Figure 4 - Article 09-8-3

CAUTION: CAREFULLY RELEASE THE COOLING SYSTEM PRESSURE WHILE REMOVING DEGAS CAP.
Carefully release the cooling system pressure, leaving the tester in place.
Seal pressure bleed.
Drive the vehicle at wide open throttle (WOT) / high load / to achieve maximum boost.
Observe whether the cooling system pressure exceeds the holding pressure noted in Step 2e.
Check for coolant venting through the degas bottle cap by listening for a hissing noise.
If the cooling system pressure is less than the holding pressure noted in Step 2, go to Step 10.
If the cooling system pressure exceeds the holding pressure noted in Step 2, and/or the degas bottle cap continuously vents with loaded engine, go to Step 8.

tonybullitt · January 16, 2015

To answer your question yes if pressure builds fast it has been egr cooler and if it takes high load and boost to build pressure it has been headgaskets in my experience also.

the_twig_187 · January 16, 2015

excellent! our shop does not have this tool so im looking to build it. was just wondering if I spent the time and the effort and money required to build this tool if it actually was useful and helped properly diag cooling system issues (egr cooler / headgaskets)

I have found a 0-30 psi pressure gauge ($19.99) at princess auto

a Tee adapter ($2.99) at princess auto

I just have to find approx 10 feet of 3/8 heater hose to complete the tool

Alex Bruene · January 16, 2015

I made my own with a $10 gauge from Princess Auto and some hose. Instead of buying a tee, I used venturi tee from recall 08T01, and just drilled out the venturi. And, that's why your shop doesn't have one!

batmantech · January 16, 2015

I made one out of a broken cooling system pressure tester that was in the garbage.

Keith Browning · January 16, 2015

I have a tee made up and use a gauge from the gauge bar though I have been meaning to buy an inexpensive gauge for this. I really don't use this set up for EGR cooler diagnosis ever as failed EGR coolers are usually either very obvious or there are better visual checks and inspections that will reveal a failed EGR cooler that are more definitive. IMHO... but this method will (hopefully) lead you in the right direction.

Head gaskets - absolutely!

Alex Bruene · January 16, 2015

Agreed. I only use mine for headgasket diagnosis.

the_twig_187 · January 16, 2015

I had a customer come in saying that when he came to a stop light, the hot air coming threw the vents goes cold until he begins to pickup speed again and it goes back to hot air. I thought "air pocket" in the cooling system, so I checked the de-gas bottle and there was no coolant at all in the bottle. I found some left over jugs of gold coolant and began to fill the de-gas bottle. It took 1 and a half jugs of coolant to fill the system to the cold fill line on the bottle. I immediately thought "EGR cooler" so I pulled the EGR valve to inspect for the prescience of coolant or moisture (none found) I looked at the EGR to up pipe to see moisture sweating around the pipe/clamp (none found) also pressure tested the cooling system and no external leaks were found and the system held pressure (18 psi) for approx. 30min

I wanted this tool to be able to drive the truck and verify if there was an internal coolant leak from the head gaskets

what other steps would you guys have done that I may have missed in this situation?